<?php

/**
 * MySQL Resource
 *
 * Resource Implementation based on the Custom API to use
 * MySQL as the storage resource for Smarty's templates and configs.
 *
 * Table definition:
 * <pre>CREATE TABLE IF NOT EXISTS `templates` (
 * `name` varchar(100) NOT NULL,
 * `modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
 * `source` text,
 * PRIMARY KEY (`name`)
 * ) ENGINE=InnoDB DEFAULT CHARSET=utf8;</pre>
 *
 * Demo data:
 * <pre>INSERT INTO `templates` (`name`, `modified`, `source`) VALUES ('test.tpl', "2010-12-25 22:00:00", '{$x="hello world"}{$x}');</pre>
 *
 * @package Resource-examples
 * @author Rodney Rehm
 */
class Smarty_Resource_Mysql extends Smarty_Resource_Custom
{
    // PDO instance
    protected $db;
    // prepared fetch() statement
    protected $fetch;
    // prepared fetchTimestamp() statement
    protected $mtime;
    
    public function __construct()
    {
        
        $dbConfig = require 'database.php';
        $connect = $dbConfig['type'] . ":host=" . $dbConfig['host'] . ";port=" . $dbConfig['port'] . ";dbname=" . $dbConfig['dbname'];
        
        try {
            if ($dbConfig['type'] == 'mysql') {
                $this->db = new Pdo($connect, $dbConfig['username'], $dbConfig['password'], array(
                        PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''));
            } else {
                $this->db = new Pdo($connect, $dbConfig['username'], $dbConfig['password']);
            }
        } catch (PDOException $e) {
            
            throw new Exception('Connection failed: ' . $e->getMessage());
        }
        $this->fetch = $this->db->prepare('SELECT modified, source FROM w_templates WHERE name = :name');
        $this->mtime = $this->db->prepare('SELECT modified FROM w_templates WHERE name = :name');
    }
    
    /**
     * Fetch a template and its modification time from database
     *
     * @param string $name template name
     * @param string $source template source
     * @param integer $mtime template modification timestamp (epoch)
     * @return void
     */
    protected function fetch($name, &$source, &$mtime)
    {
        $this->fetch->execute(array(
                'name' => $name));
        $row = $this->fetch->fetch();
        $this->fetch->closeCursor();
        if ($row) {        
            $source = stripslashes($row['source']); #取消转义
            $mtime = strtotime($row['modified']);
        } else {
            $source = null;
            $mtime = null;
        }
    }
    
    /**
     * Fetch a template's modification time from database
     *
     * @note implementing this method is optional. Only implement it if modification times can be accessed faster than loading the comple template source.
     * @param string $name template name
     * @return integer timestamp (epoch) the template was modified
     */
    protected function fetchTimestamp($name)
    {
        $this->mtime->execute(array(
                'name' => $name));
        $mtime = $this->mtime->fetchColumn();
        $this->mtime->closeCursor();
        return strtotime($mtime);
    }
}
